| The invasion of exotic weeds on the local plants and soil organisms will have a huge impact, alien plants adapted to local climatic conditions are able to grow and spread quickly, affect the local agricultural production and people's lives in the same time.The exotic weeds Iva xanthifolia has already invension to China in 80's, in recent years, it has already spread most areas of Hei Long Jiang and Liao Ning, and growth rapidly, it has a obviously inhibitory effect on the surrounding plants, and has a strong competitive capacity. And it has already invaded in farmland, seriously affected agricultural production, it has led to great difficulties to control weeds in farmland. The study the allelopathy effect of Iva xanthifolia on biological, Therefor, study the allelopathy of Iva xanthifolia, it has an important theoretical and practical value on Iva xanthifolia's control strategies and protection the of ecological environment. In this paper, we use the biometric technology and analysis equipment, system generated the allelopathy effect of Iva xanthifolia on the plants and soil microorganisms; the effect of different release ways Iva xanthifolia on the growth and development of cucumber; and further defined the composition of root exudates.Allof these provide a scientific basis to ecology research community and its use in practice .The following results can be concluded:1.We found that Iva xanthifolia has a significant inhibition on plants, specially on barnyard grass and green foxtail, the cucumber and cabbage followed, the sorghum is minimum..In crop seeds, Iva xanthifolia has a significant inhibition on red beans and cucumber , inhibition rate is 36.48%～37.77%; on soybean,cabbage and wheat, the inhibition rate is 10.11%～17.65%; on corn and sorghum there is nearly no inhibition; In weed seeds, Iva xanthifolia has obvious inhibitory effect on barnyard grass and green foxtail, with inhibition rates 65.10 %～61.11% separately.2.Iva xanthifolia has a significant inhibition on the growth and development of cucumber, and with the increase of extract concentration the inhibition increased too. The concentration 20000mg·L-1 has a significant inhibition,the geremanation inhibition ratio is 42.05%,root and sprout length inhibition ratio is 52.21～52.36%.3.Different part of Iva xanthifolia has some inhibition on the growth and development of cucumber,The stem part has a significant inhibition, the geremanation inhibition ratio is 28.89 %,root and sprout length length inhibition ratio is 60.87～83.33%.To the geremanation of cumumber,root part,leaf part,spike part has the same inhibition ratio, inhibition ratio is 27.78%.between different part of Iva xanthifolia ,stem>root>leaf>spike.All of the above indicate that:In different part of Iva xanthifolia,stem part is the best. Different release ways of Iva xanthifolia has a significant inhibition on the growth and development of cucumber, The root secretion is the most seriously, the geremanation inhibition ratio is 27.89 %,root and sprout length inhibition ratio is 31.57～31.58%.And the volatile substances of Iva xanthifolia on the growth and development of cucumber was not obviously, the geremanation inhibition ratio is 18.89%.All of the above ,in the different release ways , root secretion is the best.4. There is some inhibition effect of Iva xanthifolia root secretion on soil miccroorganism and beneficial, and with the increase of extract concentration the inhibition increased too.The inhibition is obviously to local bacteria,to Fungal the change not obviously,at 10th day ,the inhibition stop,the the max inhibition rate is 12.51%, to Bacterial 1～3th day,the inhibition increase,at 3th day,the inhibition get the top ,3～10 decreased gradually, ,after the 10th day,the inhibition stop,the max inhibition ratio is 3.71%,to Actinomyces 1～3 th day,the inhibition increase,at 3th day,the inhibition get the top ,3～6 decreased gradually,after the 10th day,the inhibition stop,the max inhibition ratio is 67.11% .The result indicated that:there are a significate inhibition from Iva xanthifolia root secretion on soil miccroorganism.The inhibition to Actinomyces is the most seriously.5.There is some inhibition effect of Iva xanthifolia root secretion on beneficial and harmful bacteria, and with the increase of extract concentration the inhibition increased too.to Rhizobium 1～3th day,the inhibition increase,at 3th day,the inhibition get the top ,3～6 decreased gradually,after the 6th day,the inhibition stop,the max inhibition ratio is 46.89%, to Fusarium 1～4th day,the inhibition increase,at 4th day,the inhibition get the top ,4～5 decreased gradually,after the5th day,the inhibition stop,the max inhibition ratio is 57.82 %.The conclusion is :there is some inhibition effect of Iva xanthifolia root secretion on soil miccroorganism and beneficial and harmful bacteria to a certain extent,if Iva xanthifolia send root secretion to the enviorment ,the bacteria near Iva xanthifolia root will be impact obvious.6. In 20000 mg·L-1 Iva xanthifolia root secretion,the nutrition composition :protein334 mg·L-1; crude fat 190 mg·L-1; total sugar114.6mg.L-1; reducing sugar 110.6mg.L-1; non-reducing sugar content 3mg.L-1.In this experiment, Iva xanthifolia root secretion have 22 kinds of main components , five kinds of hydrocarbons, acids one species, 4 kinds of alcohols, 2 kinds of ketones, 3 kinds of aldehydes, 1 kinds of acide,4 kinds of esters, heterocyclic one species, 1 kinds of terpenes. Heterocyclic as one of naphthalene compounds, it is a very dangerous environmental toxins.
|
PDF Full Text Request